The fine structure of pasta and its connection with raw material characteristics and processing conditions

Several studies focused on the semolina characteristics required to make highquality pasta. Protein characteristics were associated with pasta textural and cooking properties due to the protein role in the formation of a tenacious dough structure during mixing and of a firm viscoelastic matrix during cooking. Starch—the major component of semolina—has received much less attention. In an attempt to identify which starch (micro) structure can provide good cooking performances, the physical and chemical modifications induced by the processing conditions were determined both by conventional and advanced approaches. Regardless of semolina composition, pasta drying created a new starch structure. A low-temperature (LT) cycle promoted the formation of a less compact and more hydrophilic structure than a hightemperature (HT) cycle, as shown by protein solubility, starch accessibility to enzymatic action, swelling capacity, peak viscosity, and spectroscopic approaches. Water takes longer time to penetrate inside the HT pasta matrix. Consequently, starch gelatinization is slower, giving a higher melting temperature and confirming the presence of new ordered structure. As for raw materials, semolina characterized by high viscosity (MVAG test) resulted in a sticky and less firm product with a greater tendency to macromolecule leaching into cooking water. Multiscale and complementary approaches were used to clarify the structural properties of starch and its relationship with cooking performances also in gluten-free matrices, where the structural organisation is greatly affected by the sequence and the conditions of heating and cooling steps. Attention will be paid on understanding the relationship between starch structure and processing conditions to develop gluten-free pasta with textural properties similar to the semolina-based product.